Persistent left superior vena cava is a congenital variation of the thoracic venous system. Although it is often asymptomatic, its presence can complicate procedures such as central venous access, cardiac device implantation, and cardiothoracic surgery. Reported prevalence data are inconsistent and predominantly derived from populations with underlying cardiac pathology. This study seeks to provide a robust, evidence-based estimate of the prevalence of persistent left superior vena cava in populations not preselected for congenital heart disease. Additionally, it aims to quantify its principal anatomical configurations, including the laterality of the superior vena cava and the presence or absence of a bridging brachiocephalic vein. A systematic search was conducted using PubMed, Google Scholar, Scopus, and Web of Science. Studies documenting the prevalence of persistent left superior vena cava in populations not selected on the basis of congenital heart disease criteria were included. Statistical analysis was carried out using random-effects meta-analytic models. Eighteen studies (n = 169,835 individuals) were included. The pooled prevalence of persistent left superior vena cava was 0.61% (95% CI: 0.38-0.89), with substantial heterogeneity across studies. Subgroup analysis demonstrated higher detection rates in cadaveric investigations (2.08%) compared with interventional studies (0.38%), likely reflecting differences in detection sensitivity. Bilateral superior vena cava was observed in 0.32% of the population, whereas isolated persistent left superior vena cava occurred in 0.10%. A bridging brachiocephalic vein was present in approximately 0.11% of the total population. Although uncommon, persistent left superior vena cava is a reproducible component of thoracic venous morphology with embryological significance. Awareness of its anatomical configurations is important in diagnostic and procedural contexts, especially when a dilated coronary sinus is observed during imaging.

Facial soft tissue thickness (FSTT) includes the layers from the bone to the skin surface and is influenced by various factors. Ultrasound (US) serves as one modality for FSTT measurement. This study aimed to explore fundamental data regarding FSTT and examined the association of FSTT and sex, age, body mass index (BMI), and facial side. B-mode US was used to measure FSTT at 11 midline and 32 bilateral landmarks in 100 unembalmed cadavers within 120h postmortem. The association of FSTT with sex, age, BMI, and facial side, were analyzed by descriptive and analytical statistics, with statistical significance set at a p-value of less than 0.05. The parotid-masseteric region was the thickest with the most variation, while the nose was the thinnest. BMI played a significant role, with significant differences in FSTT across all landmarks between underweight and normal BMI groups. Females generally exhibited thicker FSTT, particularly significant difference in the mid-infraorbital, endocanthion, gonion, and mid-mandibular border areas. However, males had greater thickness in nasal and perioral regions, especially significant at the prosthion and supracanine landmarks. Aging had a minimal impact on FSTT in individuals over 50, with only the mid-philtrum and labrale inferius showing age-related significant differences. Facial asymmetry was observed, with significant variations in the lateral perioral and buccal regions between the left and right sides. Sex, age, BMI, and facial side each influence FSTT, though their effects vary in magnitude across different facial regions. This data enhances foundational facial anatomy, guides aesthetic procedures in underweight and normal-weight individuals, and supports forensic facial reconstruction.

High jugular bulb (HJB) and jugular bulb dehiscence (JBD) are anatomical variants with significant clinical implications; however, reported prevalence varies widely due to heterogeneous definitions and imaging protocols. We conducted a systematic review and meta-analysis of 49 studies, encompassing more than 43,000 temporal bones and 17,000 patients, to estimate pooled HJB and JBD prevalence. Observational studies reporting extractable prevalence data were synthesized using random-effects generalized linear mixed models with cluster-robust variance estimation. HJB definitions were harmonized into landmark-based families (internal acoustic meatus, round window/basal turn, tympanic annulus, tympanic protrusion), and separate analyses were performed for per-patient and per-ear denominators. Pooled HJB prevalence was 24.4% per patient (95% CI 16.7-34.3; prediction interval 3.8-72.4) and 16.2% per ear (10.7-23.8; PI 1.6-69.7), with extreme between-study heterogeneity (I2 > 97%). Definition-specific estimates differed systematically, with round-window/basal-turn criteria yielding approximately 22% compared with 15% for internal acoustic meatus-based definitions. JBD prevalence was 6.1% per patient (3.4-9.5) and 3.2% per ear (2.1-4.7). Meta-regression indicated that definition choice accounted for less than 10% of between-study variance, with imaging protocols, measurement planes, and clinical populations accounting for most of the remaining heterogeneity. Both variants are sufficiently common to warrant routine preoperative imaging before otologic and skull-base procedures. Given wide prediction intervals, single pooled prevalence values are not directly transportable; reporting should emphasize definition-specific estimates and imaging parameters to inform surgical planning and risk stratification.

Unexpected treatment failures can occur during middle meningeal artery embolization (MMAE) in the treatment of chronic subdural hematoma cases. This study aimed to classify variations in the anatomy of the extracranial MMA (exMMA) to improve MMAE. Five heads from body donors, 300 dry skulls, and 162 head and neck CT angiography (CTA) images were used to evaluate the overall features of the exMMA. Body donors dissection were incorporated to comprehensive exMMA representation. The distal features of the exMMA were determined by evaluating the outer osseous grooves of the foramen spinosum of the skulls. Measurements of the exMMA were performed using CTA. The angles between the maxillary artery and the exMMA were 109.5° ± 32.5° (left) and 117.1° ± 34.3° (right) (p < 0.05). The angle between the exMMA and the skull base was greater on the left side (79.24° ± 4.21°, p = 0.0017). The diameters of the exMMA were 1.45 ± 0.12mm (left) and 1.44 ± 0.13mm (right) (p = 0.82). Multiple types of accessorial foramen spinosum provided the paths for the accessorial MMA. In the new classification, five types were identified. Type A was the most common (73.15%) and represented an easily accessible MMAE type. This was followed by type C (25.62%, difficult to accessible), type D (18.83%, very difficult to accessible), type B (1.23%, fairly accessible), and type E (0.17%, inaccessible). Varying levels of interventional difficulty occur within the exMMAs classification. Careful preoperative evaluations should be performed before MMAE to determine the type of exMMA and potential interventional difficulty.

Injection of colored media remains pivotal for three‑dimensional appreciation of vascular anatomy since the pioneering work of Harvey, Ruysch and Swammerdam. Claude Gillot revived the approach for the study of the venous system by combining green‑latex infusion with post‑dissection vein painting (“colored segmentation”) to enhance anatomical education. To detail Gillot’s injection technique, evaluate its technical reliability, 400 fresh lower limbs (200 donors, mean age 75 years; Centre du Don des Corps, Paris) were irrigated with warm soapy water and injected via an ankle 19‑G butterfly into the great saphenous vein with filtered green latex (120–150 ml; 20 ml syringe; 20–30 kPa). Proximal femoral venous drainage prevented reflux. After 24 h polymerization the limbs were dissected; venous segments were painted according to a seven‑color palette. Patency, leakage and dissection time were recorded. Three exemplary specimens were photogrammetrically documented. Overall venous patency reached 93% with minimal segmental leakage (mean < 2 cm per limb). Dissection time per lower limb averaged ten hours. Gillot’s colored‑segmentation protocol provides a vivid, dependable and inexpensive platform for teaching and research in venous anatomy. Its flexibility and compatibility with digital capture surpass many contemporary embalming or silicone‑based perfusion techniques. Future work should integrate three‑dimensional models into virtual‑reality curricula and quantify learning outcomes.

Since the report in 2016 of AAV-PHP.B, a capsid variant of adeno-associated virus (AAV) capable of efficiently penetrating the mouse blood-brain barrier (BBB), numerous other BBB-penetrant capsid variants have been developed. These variants differ in their use of membrane-bound receptors expressed on vascular endothelial cells, their BBB permeability, and their tropism toward specific brain cell types. In the first half of this paper, we provide an overview of four representative BBB-penetrant AAV capsid variants-PHP.B, PHP.eB, AAV-F, and 9P31. By combining these capsids with cell type-specific promoters, it is possible to achieve transgene expression selectively in target brain cell populations via intravenous administration. In the latter half of this paper, we focus on brain cell type-specific promoters and enhancers that are compatible with AAV packaging, including those developed in our own laboratory.

Understanding the neural mechanisms underlying sensory perception remains a fundamental challenge in neuroscience. In vivo two-photon calcium imaging in behaving mice has become a widely used approach to dissect cortical dynamics during perceptual decision-making. In this protocol, we present a standardized and reproducible experimental pipeline for investigating the neural basis of visual perception at cellular resolution. After being surgically prepared, the mice were trained in a step-by-step method and reliably learned the orientation-based visual discrimination task at full contrast, achieving high performance within days and maintaining stable proficiency across sessions. Combining viral-mediated expression of genetically encoded calcium indicators with two-photon imaging, deep-layer neuronal activity in the primary visual cortex was recorded while mice were performing the multi-contrast discrimination task. The imaging data revealed diverse neuronal response profiles, providing insights into the cortical representations supporting visual perception. Our protocol provides detailed information on surgical preparation, behavioral training and data acquisition, offering educational and practical guidance for investigating sensory processing and perceptual decision-making in the mammalian cortex.

Different head and neck anatomical structures, such as the temporomandibular joint, carotid arteries and their branches, styloid process, hyoid and thyroid cartilage, are subjected to anatomical variations. A range of novel and rare anatomical variants were found during the anatomical exploration of a DICOM file. The archived angioCT file of a 63-year-old male was examined anatomically. There were no pathological processes or other artefacts to distort the anatomical patterns. The imprint of Farabeuf's knocker (posterior zygomatic tubercle) on the posterior side of the right mandibular condyle was found. This is an anatomical novelty. Rare neck variations were found: a right-tilted and collapsed hyoid bone over the thyroid cartilage and the agenesis of the left superior horn of this cartilage. Variations of the external carotid arteries' branches were observed. A right thyrolingual trunk gave off a superior thyroid artery that supplied both thyroid lobes with distinctive right and left branches, the opposite superior thyroid artery being absent. On both sides, the superficial temporal artery coursed over the temporomandibular joints. The right internal carotid artery coiled immediately beneath the skull base. It is recommended that CT scans be carefully explored, as various concomitant anatomical variations, including rare or previously unreported findings, may be encountered.

Chemical fixation is essential in immunohistochemistry for detecting molecular localization. The gold-standard fixative for immunohistochemistry is 4% paraformaldehyde (PFA); however, its properties-such as tissue shrinkage and protein cross-linking through methylene bridges-often restrict antibody access, posing challenges to achieving specific binding reactions. This is particularly true for receptors and ion channels condensed in the synaptic cleft, postsynaptic density, or trigger zone of action potentials. To overcome this problem, several laboratories have attempted antigen-exposure techniques. Recently, we demonstrated that fixation by glyoxal, a dialdehyde with two carbon atoms, enables specific detection of molecular groups that are difficult to be detected in PFA-fixed tissues. Here, we summarize the advantages and precautions in the use of glyoxal fixative.